(a) Field of the Invention
The present invention relates to a method and apparatus for forming grooves, and more particularly to forming grooves in the mitred ends of frame members, such as picture frame members, to enable these frame members to be easily joined together by fasteners to form the completed frame.
(b) Background of the Invention
Picture frames commonly have a rectangular configuration and are formed by four straight frame members which join to one another at mitred ends thereof. A common method of joining the frame members to one another is to apply glue or some other bonding agent to the mitred surfaces, place the surfaces against one another in the desired configuration, and then clamp the frame members together in that configuration for a period of time.
To enable the joining process to be carried out more effectively, there have been various proposals in the prior art to form the mitred ends of the frame members with slotlike grooves or recesses which can receive fasteners of various configurations. Then, the mitred ends of the frame members can be positioned against one another, with the fastening members being inserted in the matching grooves or recesses to hold the frame members together.
These grooves or recesses must be formed with reasonable precision, and to enable these grooves to be formed efficiently, there have been proposals in the prior art to provide machines specially made to form such grooves in the mitred ends of these frame members. Also, there exists in the prior art other types of machines to form slots or grooves in various members, such as doors, panels, etc. A search of the patent literature has disclosed a number of these devices, and these are listed below.
U.S. Pat. No. 4,593,734--Wallace, discloses a frame routing apparatus where the two frame members are held in a base member which can be moved laterally relative to a router. The mitred ends of the frame members face upwardly and rearwardly. A router is mounted between the mitred ends of the frame members and as the base is moved from one side to the other, the recesses or grooves are formed in the mitred ends of the frame members. Suitable stop members are also provided.
U.S. Pat. No. 4,653,557--Merrill, shows a slot cutting machine for forming the recess shown in FIGS. 4, 5 and 6 of that patent. The frame member to be cut is secured to a carriage-like device and slid into a rotating fixed cutter 44 to form the recess.
U.S. Pat. No. 4,632,160--Wright, shows a molding routing apparatus where the molding is mounted to a fixed base in a manner that the position of the molding ca be adjusted laterally. There are a pair of motors carrying routing devices that can be moved into the molding to form the desired recesses.
U.S. Pat. No. 4,615,654--Shaw, shows a portable router used for cutting slots in the edge of a cabinet door to receive the wings of hinges. There is a frame which rests on the door when the slot is cut, and it is located on the door by a selected one of two guides.
U.S. Pat. No. 4,112,987--Pachnik, shows a "radius router guide" where the router is mounted to a frame that is, in turn, mounted to the end of a timber. The frame is pivotally mounted so that the router can be moved in an arcuate path over an end portion of the timber, and also be moved laterally back and forth in a frame. Thus, a circularly curved end surface can be formed on the timber.
U.S. Pat. No. 3,692,075--White, shows a routing tool where the router is movable to form hinge slots in doors or the like. The material to be cut is held in a fixed position, and the router is moved to make the cut. Three different forms of the invention are shown, and in the first embodiment, adjustable stop members are provided to position the workpiece at different locations.
U.S. Pat. No. 3,643,713--Massetani, shows a machine to manufacture grooves in folding elements and doors or the like, and there is an endless tape carrying cutting elements, with this tape being mounted on a pair of wheels.
U.S. Pat. No. 3,547,171--Jacumin, shows a woodworking tool where the wood is moved relative to several cutting tools, including a routerlike device.
U.S. Pat. No. 2,929,421--Webb, shows a machine tool in which there is a work carrier 28, which is supported on a rod 24. The support member is located on the rod 24 by springs 25 and 27 so that the support is held centered.
U.S. Pat. No. 2,630,151--Turnbull, shows a router support means in which there is a support 30 on which the router both tilts and slides. The router movement is limited by a series of adjustable stops.
U.S. Pat. No. 2,354,639--Seymour, simply shows a cutter for forming a groove having an expanded interior portion.
U.S. Pat. No. 1,895,054--Steinmeyer, shows a woodworking machine which is clamped to a sash frame or the like. The router is moved along guide means to cut grooves and the like in the work.
U.S. Pat. No. 1,814,702--Jensen, shows a machine for forming "T" shaped grooves in wood. The major axis of the groove is cut with a sawblade, and the cross is formed by a fixed blade 36.